Flakpanzer IV Wirbelwind and Ostwind

Ostwind

Flakpanzer IV Ostwind

In the early stages of the war, German Army relied on towed anti-aircraft guns and then on gun mounted on variety of trucks and half-tracked vehicles. Specialized flakpanzers were produced in small numbers and were considered "temporary" until proper vehicles are develop.

As the war progressed, German Luftwaffe was no longer in complete control of the airspace over the battlefield. This was especially dangerous to the panzer units, first on the Eastern Front and then on the Western Front. Mobile air-defence was needed for both offensive operations to support fast moving panzer units and for defensive operations to provide anti-aircraft cover for defending or withdrawing units under attack.

Wirbelwind and Ostwind were successors to the Flakpanzer IV Mobelwagen (armed with 37mm Flak 43 L/89) – "interim solution" produced before the introduction of the real Flakpanzer.

In July of 1944, prototype of Ostwind (Eastwind) – an air defense armored vehicle build on Panzerkampfwagen IV‘s proven chassis was produced. Its design was very similar to that of Flakpanzer IV Wirbelwind (Whirlwind) which prototype was build in May of 1944 and was to become the first true Flakpanzer.

Both vehicles were build on retired or battle damaged Panzerkampfwagen IV (mainly Ausf F/G) chassis/components returned from the front for major repairs. The concept of Wirbelwind was proposed by SS-Hauptsturmführer Karl Wilhelm Krause, an officer from 12th SS Panzer Division "Hitler Jugend". In the early summer of 1944, Krause proposed to mount four barrelled 20mm Flak 38 L/112.5 gun on PzKpfw IV‘s chassis. During the fighting in Normandy in the Summer of 1945, his flak unit was credit with shooting down 45 allied planes.

Wirbelwind and Ostwind were fitted with very similar (especially designed) open-top (Wirbelwind’s turret had 9 side panels and Ostwind’s had 6 side panels) turrets mounted in the place of standard turrets. Both turrets were made to accommodate the Flak and as result an overall profile of a vehicle being much higher in comparison to a regular Panzerkampfwagen IV tank.

Ostwind’s turret was nicknamed Keksdose – cookie tin. Main difference was that Wirbelwind was armed with quadruple 20mm Flak 38 L/112.5 guns, while Ostwind was armed with single 37mm Flak 43 L/89 gun. Both guns were used against ground targets as well, proving to very effective against unarmored or lightly armored vehicles.

20mm Flak proved to be less effective than 37mm Flak and was eventually replaced by it. Both were produced by Ostbau Works in Sagan, Silesia in limited numbers due to the material shortages and the fact that Ostbau Works moved to facilities of Deutsche Eisenwerke in Teplitz and Duisburg due to danger of being overrun by the Soviets.

Overall from May to November of 1944, only 87(or 105) Wirbelwinds were made, contrary to only 44(or 43) Ostwinds produced from July 1944 to March of 1945. Both vehicles were issued to Flugabwehrzug (AA platoons) units of Panzer Divisions.

There were never enough of them to equip frontline units, which were in the need for adequate mobile AA defense. Both proved to be very effective against low flying aircraft. The interesting fact is that prototype Ostwind was combat tested by 1st Waffen SS Panzer Division "Leibstandarte SS Adolf Hitler" during the Ardennes Offensive (December 16 to 22 of 1944) and returned to factory undamaged.

In late 1945, there were plans to increase the firepower of both Wirbelwind and Ostwind.

It was planned to rearm existing Wirbelwinds with four 30mm MK103/28 or MK103/38 guns, capable of firing 1600 rounds per minute. In December of 1944, Ostbau produced only one prototype designated Zerstorer 45 (Destroyer 45) – 3cm Flakvierling MK103/108 auf Sfl PzKpfw IV. Same concept was incorporated into rearming of the Ostwind with two 37mm Flak 43 or Flak 44 guns or 30mm Mauser MK103 cannon. In January of 1945, Ostbau was able to produce one prototype designated Ostwind II (3.7cm Flakzwilling 44 auf Sfl PzKpfw IV) , while 100 were ordered. In 1945, it was decided to utilize obsolete at the time PzKpfw III and mount it with Wirbelwind (designated as 2cm Flakvierling 38 auf Slf PzKpfw III) or Ostwind (designated as 3.7cm Flak 43 auf Slf PzKpfw III) turrets, designated as Flakpanzer III. 90 were ordered but the end of the war terminated the production. Eventually, all of Flakpanzers were to be replaced by newly designed Flakpanzer IV Kugelblitz in the early 1945.